DP-300 Hard Questions — 25 Difficult Questions

Question 1

You run the query in the exhibit on an Azure SQL Database. The result shows high wait_time_ms for PAGEIOLATCH_SH waits. What does this indicate?

Accepted Answer

I/O subsystem bottleneck for read operations. PAGEIOLATCH_SH waits indicate that a query is waiting for a data page to be read from disk into the buffer pool, which is an I/O operation. High wait_time_ms for this wait type typically points to an I/O subsystem bottleneck for read operations, making option A correct. Option B (CPU bottleneck) is incorrect because PAGEIOLATCH_SH is related to I/O, not CPU. Option C (blocking) is incorrect because blocking is associated with LOCK waits, not PAGEIOLATCH_SH. Option D (memory pressure) is incorrect; while memory pressure can increase physical I/O, the wait type itself specifically indicates I/O latency for reading pages from disk.

Answer

CPU bottleneck

Answer

Blocking between concurrent transactions

Answer

Memory pressure

Question 2

You have an Azure SQL Managed Instance with a large number of databases. You need to monitor the storage space used by each database to proactively manage capacity. Which tool should you use?

Accepted Answer

Azure SQL Analytics (preview). Azure SQL Analytics (preview) in Azure Monitor provides a consolidated monitoring solution for Azure SQL databases and managed instances, including detailed storage usage per database. Option A is wrong because Query Performance Insight focuses on query-level metrics like query duration and CPU usage, not per-database storage. Option B is wrong because Automatic tuning is a feature that automatically indexes and optimizes query plans, not a monitoring tool. Option C is wrong because Intelligent Insights provides proactive performance diagnostics and anomaly detection, but does not directly per-database storage monitoring. Therefore, only Azure SQL Analytics meets the requirement.

Answer

Query Performance Insight

Answer

Automatic tuning

Answer

Intelligent Insights

Question 3

You are configuring security for an Azure SQL Managed Instance. The instance will host a critical application that requires always encrypted with secure enclaves. Which TWO actions must you take to support this feature? (Choose two.)

Accepted Answer

Select the Intel Software Guard Extensions (Intel SGX) enclave type.. Always Encrypted with secure enclaves on Azure SQL Managed Instance requires the Intel Software Guard Extensions (Intel SGX) enclave type. Intel SGX is the only supported enclave technology for this feature on managed instances, providing a trusted execution environment that protects sensitive data in memory during cryptographic operations.

Answer

Configure the column master key to be stored in Azure Key Vault.

Answer

Enable the enclave attestation policy on the managed instance.

Answer

Enable Virtualization-Based Security (VBS) enclave type.

Question 4

A retail company is migrating its on-premises SQL Server database to Azure SQL Database. The database has a table with 500 million rows and receives 10,000 INSERT operations per second during peak hours. The application requires read-committed snapshot isolation. Which Azure SQL Database tier and configuration should the DBA recommend to minimize cost while meeting performance requirements?

Accepted Answer

Hyperscale tier with 4 vCores. The Hyperscale tier with 4 vCores is correct because it supports up to 100 TB of storage, provides fast scaling for high-volume INSERT workloads (10,000 rows/second), and natively supports read-committed snapshot isolation (RCSI) without additional configuration. It minimizes cost compared to Business Critical while offering the necessary performance and isolation level for a 500-million-row table.

Answer

Business Critical tier with 8 vCores

Answer

Serverless tier with auto-pause

Answer

General Purpose tier with 2 vCores

Question 5

You are reviewing an Azure SQL Database audit policy configuration. The policy is set to audit successful and failed database authentication events. You notice that audit logs are being written to both Azure Blob Storage and Azure Monitor. However, you are concerned about security of the storage account access key in the policy. What is the recommended approach to securely reference the storage account?

Accepted Answer

Configure the server's system-assigned managed identity and grant it access to the storage account.. Using a system-assigned managed identity for the Azure SQL Database logical server eliminates the need to store a storage account access key in the audit policy configuration. Managed identities provide a secure, Azure AD-backed identity that can be granted specific permissions (e.g., Storage Blob Data Contributor) on the storage account, ensuring that access is controlled via RBAC rather than a static key. This approach aligns with security best practices by removing the risk of key exposure or rotation failures.

Answer

Remove the storageAccountAccessKey property and rely on the storage endpoint.

Answer

Use a different storage account with a key that expires daily.

Answer

Disable the Azure Monitor destination and only use Blob Storage.

Question 6

Your company uses Azure SQL Database with the Hyperscale service tier. You notice that the database is experiencing high I/O latency during peak hours. After analyzing the query performance, you determine that the primary bottleneck is due to log write throughput. You need to reduce log write latency without changing the service tier. What should you do?

Accepted Answer

Scale up to a higher Hyperscale service objective.. Scaling up to a higher Hyperscale service objective increases the log write throughput by provisioning more log I/O capacity and faster storage. Since the bottleneck is specifically log write latency, and you cannot change the service tier, increasing the service objective within Hyperscale directly addresses the issue by allocating more resources to the log write path.

Answer

Configure Query Store hints to force parameterization.

Answer

Enable read scale-out to offload read queries.

Answer

Increase the MAXDOP setting for the database.

Question 7

You are configuring performance optimization for an Azure SQL Database that uses the Hyperscale service tier. The database has heavy read-write workloads. Which THREE actions should you take to optimize performance?

Accepted Answer

Create nonclustered columnstore indexes on large fact tables.. Options A, C, and D are correct. Hyperscale benefits from nonclustered indexes on read-intensive tables, accelerated database recovery reduces log IO, and read-scale replicas distribute read load. Option B is wrong because Hyperscale does not support resource governor. Option E is wrong because increasing service tier is not an optimization action.

Answer

Configure resource governor to limit CPU usage.

Answer

Increase the service tier to Business Critical.

Question 8

Refer to the exhibit. An administrator is trying to perform a point-in-time restore for a managed instance database. The output shows the state of the instance and databases. What is the most likely reason db1 shows 'Restoring' status?

Accepted Answer

The database is being restored from a geo-redundant backup.. The 'Restoring' status on db1 indicates that a restore operation is currently in progress on that database. The geo-backup list shows an available backup, which might be used for a geo-restore or point-in-time restore that is ongoing.

Answer

The database is being upgraded to a new service tier.

Answer

The database is corrupted and Azure is automatically repairing it.

Answer

The database is in the process of replication to a secondary region.

Question 9

You are monitoring an Azure SQL Database using Query Performance Insight and notice that a specific query has a high average duration and high CPU usage. The query plan shows a clustered index scan on a large table. Which two actions should you take to optimize performance? (Choose two.)

Accepted Answer

Update statistics on the table to ensure the optimizer has current information.. Updating statistics provides the query optimizer with current data distribution information, which can lead to a more efficient query plan, potentially avoiding the clustered index scan. In Azure SQL Database, stale statistics are a common cause of suboptimal plans, and updating them is a low-cost, non-disruptive first step before considering index changes.

Answer

Rebuild the clustered index to reduce fragmentation.

Answer

Force a different query plan using Query Store hints.

Answer

Increase the DTU service tier of the database.

Question 10

Which THREE factors should you consider when choosing between vCore and DTU purchase models for Azure SQL Database performance optimization?

Accepted Answer

DTU is simpler for customers who want a bundled metric.. The DTU (Database Transaction Unit) model bundles compute, storage, and I/O into a single, simple metric, making it easier for customers who want a straightforward, pre-configured performance tier without needing to manage individual resources. This contrasts with the vCore model, which requires separate configuration of vCores, memory, and storage, offering more granular control but greater complexity.

Answer

Only vCore supports Azure Hybrid Benefit.

Answer

Only DTU supports elastic pools.

Question 11

You are automating the scaling of an Azure SQL Database based on workload patterns. The database uses the DTU purchasing model. You need to ensure that scaling actions do not cause connection drops. Which scaling method should you use?

Accepted Answer

Use the Azure portal or PowerShell to change the service tier within the same DTU tier (e.g., S2 to S3) to avoid downtime.. Azure SQL Database supports online scaling without connection drops when scaling within the same DTU tier (e.g., from S2 to S3). This is because the database remains online and the operation is a metadata change. Option D is correct. Option A is incorrect: creating a new database and using point-in-time restore does not scale the existing database and causes downtime during restore. Option B is incorrect: ALTER DATABASE with ONLINE option is for file operations, not for scaling service tiers. Option C is incorrect: Elastic Database Jobs are for scheduling scripts across databases, not for scaling operations.

Answer

Create a new database at the target size and use point-in-time restore to copy data.

Answer

Scale using the ALTER DATABASE T-SQL command with the ONLINE option.

Answer

Use Elastic Database Jobs to schedule scaling during maintenance windows.

Question 12

Which THREE components are required to configure a failover group for Azure SQL Database? (Choose three.)

Accepted Answer

At least one database on the primary server.. Options B, C, and D are correct. A failover group requires a primary server, a secondary server, and at least one database on the primary server. Option A is incorrect because the failover group listener is automatically created and does not need to be separately configured. Option E is incorrect because an elastic pool is optional; failover groups can contain individual databases or elastic pools.

Answer

Failover group listener.

Answer

An elastic pool.

Question 13

You have an Azure SQL Managed Instance configured with a failover group for disaster recovery. The primary instance is in the East US region and the secondary is in West US. You need to perform a planned failover for maintenance with zero data loss. What is the correct sequence of steps?

Accepted Answer

Use the Azure portal to perform a planned failover for the failover group.. To perform a planned failover with zero data loss for an Azure SQL Managed Instance failover group, you should use the Azure portal (or PowerShell/CLI) to initiate a planned failover. This ensures that all transactions are synchronized before switching roles, preventing data loss. Option A is incorrect because taking the primary offline before failover would cause downtime and potential data loss. Option C is incorrect because scaling down does not facilitate a planned failover. Option D is incorrect because removing the failover group would break replication and is unnecessary.

Answer

Take the primary instance offline, then failover.

Answer

Scale down the primary to reduce cost, then failover.

Answer

Remove the failover group, perform maintenance, then recreate the failover group.

Question 14

You have a SQL Server on Azure VM that is part of a failover cluster instance (FCI). The cluster nodes are in an availability set. You need to ensure that the database can tolerate a complete Azure region failure. What should you add to the current architecture?

Accepted Answer

Deploy a second FCI in a different Azure region and configure SQL Server log shipping or availability group between the FCIs.. Deploying a second FCI in a different Azure region and configuring SQL Server log shipping or an availability group between the FCIs provides disaster recovery across regions. Option A is incorrect because adding a node in a different availability zone within the same region does not protect against a complete region failure. Option C is incorrect because geo-redundant backup storage only protects backups, not provide continuous replication for the database. Option D is incorrect because active geo-replication is a feature of Azure SQL Database, not SQL Server on Azure VM.

Answer

Add another node to the existing FCI in a different availability zone.

Answer

Configure geo-redundant backup storage for the SQL Server VMs.

Answer

Create an Azure SQL Database with active geo-replication and migrate the database.

Question 15

Your company has a SQL Server on Azure VM hosting a critical database. You need to ensure high availability with automatic failover and no data loss during a planned patching event. The solution must minimize cost. Which configuration should you use?

Accepted Answer

Deploy two Azure VMs in an availability set, configure SQL Server Always On availability group with synchronous commit and automatic failover.. Deploying two Azure VMs in an availability set and configuring SQL Server Always On availability group with synchronous commit and automatic failover meets the requirements of high availability with automatic failover and no data loss during planned patching (by performing a manual failover). This solution minimizes cost compared to Azure SQL Database Managed Instance or geo-replication. Option A is incorrect because migrating to Azure SQL Database Managed Instance is a different platform, not SQL Server on Azure VM, and geo-replication is for disaster recovery, not planned patching. Option B is incorrect because log shipping is not automatic and can result in data loss. Option C is incorrect because a single VM with FCI using Storage Spaces Direct does not provide automatic failover for planned patching; it requires a secondary node.

Answer

Migrate to Azure SQL Database Managed Instance and configure geo-replication.

Answer

Configure log shipping with a secondary VM in another region.

Answer

Use a single VM with a failover cluster instance (FCI) using Storage Spaces Direct.

Question 16

Your company uses Azure SQL Database with active geo-replication for disaster recovery. The primary database is in the West Europe region. You need to perform a planned failover to the secondary in North Europe for a maintenance window. Which THREE actions should you take? (Choose three.)

Accepted Answer

After failover, verify that the new secondary (in West Europe) is configured as a readable secondary.. The correct actions are C, D, and E. For a planned failover during a maintenance window, you should initiate a planned failover (no data loss) from the Azure portal or PowerShell (E) to ensure all transactions are synchronized before switching. After failover, verify that the new secondary (in West Europe) is configured as a readable secondary (C) to maintain disaster recovery capabilities. Additionally, update the application connection strings to point to the new primary in North Europe (D). Option A is incorrect because a forced failover could cause data loss and is intended for unplanned outages. Option B is incorrect because seeding of the new secondary happens automatically via geo-replication.

Answer

Initiate a forced failover to ensure the fastest switchover.

Answer

Manually seed the new secondary database after failover.

Question 17

You are managing an Azure SQL Database that uses Intelligent Insights. You receive an alert that there is a performance issue with a specific query. You need to analyze the root cause. What should you use?

Accepted Answer

Query Store to review query execution plans and wait statistics. Query Store is the correct tool because it captures historical execution plans, runtime statistics, and wait statistics for individual queries, allowing you to pinpoint the root cause of a performance regression. Intelligent Insights provides high-level diagnostics but not the granular per-query plan and wait data needed for deep analysis of a specific query issue.

Answer

Intelligent Insights report

Answer

Automatic Tuning recommendations

Answer

Azure Monitor metrics for the database

Question 18

Refer to the exhibit. You are reviewing an ARM template for an Azure SQL Database backup retention policy. The database is in a business-critical environment that requires point-in-time restore (PITR) for the last 28 days. What is the issue with this configuration?

Accepted Answer

Long-term retention properties (weeklyRetention, monthlyRetention, yearlyRetention) are not valid in a backupShortTermRetentionPolicies resource.. The ARM template shows both short-term retention (PITR) and long-term retention (LTR) properties. However, the resource type is 'backupShortTermRetentionPolicies', which only supports short-term retention properties like retentionDays. Long-term retention properties (weeklyRetention, monthlyRetention, yearlyRetention) belong to a different resource type ('backupLongTermRetentionPolicies'). Including them in the same resource will cause a deployment error. Option B correctly identifies this. Option A is incorrect because the JSON syntax is valid (camelCase is used in ARM templates). Option C is incorrect because diffBackupIntervalInHours is not relevant to this issue. Option D is incorrect because 28 days is within the allowed range for PITR (up to 35 days).

Answer

The JSON syntax is invalid because property names use camelCase instead of PascalCase.

Answer

The diffBackupIntervalInHours should be 12 for a business-critical database.

Answer

The retentionDays value of 28 exceeds the maximum allowed for PITR.

Question 19

Which TWO statements about Azure SQL Database zone-redundant configuration are true? (Choose two.)

Accepted Answer

It can be enabled during database creation or by updating an existing database.. Options B and D are correct. Zone-redundant configuration can be enabled during database creation or by updating an existing database (B), and it provides resilience within a single Azure region across multiple availability zones (D). Option A is incorrect because zone-redundant configuration does not require a failover group; failover groups are used for geo-replication, not for zone redundancy. Option C is incorrect because zone-redundant configuration is available in both the General Purpose and Business Critical service tiers. Option E is incorrect because the cost impact varies by tier: General Purpose tier does not incur additional cost for zone redundancy, while Business Critical does; thus, the blanket statement that it always incurs additional cost is false.

Answer

It requires a failover group to be configured.

Answer

It is only available in the Business Critical service tier.

Answer

It incurs additional cost compared to non-zone-redundant configurations.

Question 20

Refer to the exhibit. A PowerShell script is used to move an Azure SQL Database into an elastic pool. The script runs without error. Which condition must be true before the script runs?

Accepted Answer

The database must be in the same server as the elastic pool. Moving a database into an elastic pool requires the database to be in the same server as the pool. Option A is wrong because the elastic pool must be in the same server as the database, not a different server. Option C is wrong because the database can be any service tier (Basic, Standard, Premium, etc.) as long as it fits within the pool's resource limits. Option D is wrong because the database size can be any size up to the pool's max size limit, which is not necessarily less than 10 GB.

Answer

The elastic pool must be in a different server

Answer

The database must be in the Basic tier

Answer

The database size must be less than 10 GB